Filament turnover stabilizes contractile cytoskeletal structures

Vital cellular processes depend on contractile stresses generated by the actin cytoskeleton. Commonly, the turnover of actin filaments in the corresponding structures is large. We introduce a mesoscopic theoretical description of motor-filament systems that accounts for filament nucleation, growth, and disassembly. To analyze the dynamic equations, we introduce an expansion of the filament densities in terms of generalized Laguerre polynomials. We find that filament turnover significantly stabilizes contractile structures against rupture. Finally, we relate the mesoscopic description to a phenomenological theory of cytoskeletal dynamics.